This patch adds prefetch support to access nand flash in mpu mode. This patch also adds 8-bit nand support (omap_read/write_buf8). Prefetch can be used for both 8- and 16-bit devices.
Signed-off-by: Vimal Singh <[email protected]> --- arch/arm/mach-omap2/gpmc.c | 63 ++++++++++++- arch/arm/plat-omap/include/mach/gpmc.h | 4 drivers/mtd/nand/Kconfig | 8 + drivers/mtd/nand/omap2.c | 158 +++++++++++++++++++++++++++++++-- 4 files changed, 225 insertions(+), 8 deletions(-) Index: mtd-2.6/arch/arm/mach-omap2/gpmc.c =================================================================== --- mtd-2.6.orig/arch/arm/mach-omap2/gpmc.c +++ mtd-2.6/arch/arm/mach-omap2/gpmc.c @@ -57,6 +57,11 @@ #define GPMC_CHUNK_SHIFT 24 /* 16 MB */ #define GPMC_SECTION_SHIFT 28 /* 128 MB */ +#define PREFETCH_FIFOTHRESHOLD (0x40 << 8) +#define CS_NUM_SHIFT 24 +#define ENABLE_PREFETCH (0x1 << 7) +#define DMA_MPU_MODE 2 + static struct resource gpmc_mem_root; static struct resource gpmc_cs_mem[GPMC_CS_NUM]; static DEFINE_SPINLOCK(gpmc_mem_lock); @@ -386,6 +391,63 @@ void gpmc_cs_free(int cs) } EXPORT_SYMBOL(gpmc_cs_free); +/** + * gpmc_prefetch_enable - configures and starts prefetch transfer + * @cs: nand cs (chip select) number + * @dma_mode: dma mode enable (1) or disable (0) + * @u32_count: number of bytes to be transferred + * @is_write: prefetch read(0) or write post(1) mode + */ +int gpmc_prefetch_enable(int cs, int dma_mode, + unsigned int u32_count, int is_write) +{ + uint32_t prefetch_config1; + + if (!(gpmc_read_reg(GPMC_PREFETCH_CONTROL))) { + /* Set the amount of bytes to be prefetched */ + gpmc_write_reg(GPMC_PREFETCH_CONFIG2, u32_count); + + /* Set dma/mpu mode, the prefetch read / post write and + * enable the engine. Set which cs is has requested for. + */ + prefetch_config1 = ((cs << CS_NUM_SHIFT) | + PREFETCH_FIFOTHRESHOLD | + ENABLE_PREFETCH | + (dma_mode << DMA_MPU_MODE) | + (0x1 & is_write)); + gpmc_write_reg(GPMC_PREFETCH_CONFIG1, prefetch_config1); + } else { + return -EBUSY; + } + /* Start the prefetch engine */ + gpmc_write_reg(GPMC_PREFETCH_CONTROL, 0x1); + + return 0; +} +EXPORT_SYMBOL(gpmc_prefetch_enable); + +/** + * gpmc_prefetch_reset - disables and stops the prefetch engine + */ +void gpmc_prefetch_reset(void) +{ + /* Stop the PFPW engine */ + gpmc_write_reg(GPMC_PREFETCH_CONTROL, 0x0); + + /* Reset/disable the PFPW engine */ + gpmc_write_reg(GPMC_PREFETCH_CONFIG1, 0x0); +} +EXPORT_SYMBOL(gpmc_prefetch_reset); + +/** + * gpmc_prefetch_status - reads prefetch status of engine + */ +int gpmc_prefetch_status(void) +{ + return gpmc_read_reg(GPMC_PREFETCH_STATUS); +} +EXPORT_SYMBOL(gpmc_prefetch_status); + static void __init gpmc_mem_init(void) { int cs; @@ -452,6 +514,5 @@ void __init gpmc_init(void) l &= 0x03 << 3; l |= (0x02 << 3) | (1 << 0); gpmc_write_reg(GPMC_SYSCONFIG, l); - gpmc_mem_init(); } Index: mtd-2.6/arch/arm/plat-omap/include/mach/gpmc.h =================================================================== --- mtd-2.6.orig/arch/arm/plat-omap/include/mach/gpmc.h +++ mtd-2.6/arch/arm/plat-omap/include/mach/gpmc.h @@ -103,6 +103,10 @@ extern int gpmc_cs_request(int cs, unsig extern void gpmc_cs_free(int cs); extern int gpmc_cs_set_reserved(int cs, int reserved); extern int gpmc_cs_reserved(int cs); +extern int gpmc_prefetch_enable(int cs, int dma_mode, + unsigned int u32_count, int is_write); +extern void gpmc_prefetch_reset(void); +extern int gpmc_prefetch_status(void); extern void __init gpmc_init(void); #endif Index: mtd-2.6/drivers/mtd/nand/Kconfig =================================================================== --- mtd-2.6.orig/drivers/mtd/nand/Kconfig +++ mtd-2.6/drivers/mtd/nand/Kconfig @@ -80,6 +80,14 @@ config MTD_NAND_OMAP2 help Support for NAND flash on Texas Instruments OMAP2 and OMAP3 platforms. +config MTD_NAND_OMAP_PREFETCH + bool "GPMC prefetch support for NAND Flash device" + depends on MTD_NAND && MTD_NAND_OMAP2 + default y + help + The NAND device can be accessed for Read/Write using GPMC PREFETCH engine + to improve the performance. + config MTD_NAND_TS7250 tristate "NAND Flash device on TS-7250 board" depends on MACH_TS72XX Index: mtd-2.6/drivers/mtd/nand/omap2.c =================================================================== --- mtd-2.6.orig/drivers/mtd/nand/omap2.c +++ mtd-2.6/drivers/mtd/nand/omap2.c @@ -112,6 +112,16 @@ static const char *part_probes[] = { "cmdlinepart", NULL }; #endif +#ifdef CONFIG_MTD_NAND_OMAP_PREFETCH +static int use_prefetch = 1; + +/* "modprobe ... use_prefetch=0" etc */ +module_param(use_prefetch, bool, 0); +MODULE_PARM_DESC(use_prefetch, "enable/disable use of PREFETCH"); +#else +const int use_prefetch; +#endif + struct omap_nand_info { struct nand_hw_control controller; struct omap_nand_platform_data *pdata; @@ -124,6 +134,7 @@ struct omap_nand_info { unsigned long phys_base; void __iomem *gpmc_cs_baseaddr; void __iomem *gpmc_baseaddr; + void __iomem *nand_pref_fifo_add; }; /** @@ -189,6 +200,40 @@ static void omap_hwcontrol(struct mtd_in } /** + * omap_read_buf8 - read data from NAND controller into buffer + * @mtd: MTD device structure + * @buf: buffer to store date + * @len: number of bytes to read + */ +static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len) +{ + struct nand_chip *nand = mtd->priv; + u_char *p = (u_char *)buf; + + while (len--) + *p++ = __raw_readb(nand->IO_ADDR_R); +} + +/** + * omap_write_buf8 - write buffer to NAND controller + * @mtd: MTD device structure + * @buf: data buffer + * @len: number of bytes to write + */ +static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len) +{ + struct omap_nand_info *info = container_of(mtd, + struct omap_nand_info, mtd); + u_char *p = (u_char *)buf; + + while (len--) { + writeb(*p++, info->nand.IO_ADDR_W); + while (GPMC_BUF_EMPTY == (readl(info->gpmc_baseaddr + + GPMC_STATUS) & GPMC_BUF_FULL)); + } +} + +/** * omap_read_buf16 - read data from NAND controller into buffer * @mtd: MTD device structure * @buf: buffer to store date @@ -224,6 +269,93 @@ static void omap_write_buf16(struct mtd_ ; } } + +/** + * omap_read_buf_pref - read data from NAND controller into buffer + * @mtd: MTD device structure + * @buf: buffer to store date + * @len: number of bytes to read + */ +static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len) +{ + struct omap_nand_info *info = container_of(mtd, + struct omap_nand_info, mtd); + uint32_t pfpw_status = 0, r_count = 0; + int ret = 0; + u32 *p = (u32 *)buf; + + /* take care of subpage reads */ + for (; len % 4 != 0; ) { + *buf++ = __raw_readb(info->nand.IO_ADDR_R); + len--; + } + p = (u32 *) buf; + + /* configure and start prefetch transfer */ + ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0); + if (ret) { + /* PFPW engine is busy, use cpu copy methode */ + if (info->nand.options & NAND_BUSWIDTH_16) + omap_read_buf16(mtd, buf, len); + else + omap_read_buf8(mtd, buf, len); + } else { + do { + pfpw_status = gpmc_prefetch_status(); + r_count = ((pfpw_status >> 24) & 0x7F) >> 2; + __raw_readsl(info->nand_pref_fifo_add, p, r_count); + p += r_count; + len -= r_count << 2; + } while (len); + } + /* disable and stop the PFPW engine */ + gpmc_prefetch_reset(); +} + +/** + * omap_write_buf_pref - write buffer to NAND controller + * @mtd: MTD device structure + * @buf: data buffer + * @len: number of bytes to write + */ +static void omap_write_buf_pref(struct mtd_info *mtd, + const u_char *buf, int len) +{ + struct omap_nand_info *info = container_of(mtd, + struct omap_nand_info, mtd); + uint32_t pfpw_status = 0, w_count = 0; + int i = 0, ret = 0; + u16 *p = (u16 *) buf; + + /* take care of subpage writes */ + if (len % 2 != 0) { + writeb(*buf, info->nand.IO_ADDR_R); + p = (u16 *)(buf + 1); + len--; + } + + /* configure and start prefetch transfer */ + ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x1); + if (ret) { + /* PFPW engine is busy, use cpu copy methode */ + if (info->nand.options & NAND_BUSWIDTH_16) + omap_write_buf16(mtd, buf, len); + else + omap_write_buf8(mtd, buf, len); + } else { + pfpw_status = gpmc_prefetch_status(); + while (pfpw_status & 0x3FFF) { + w_count = ((pfpw_status >> 24) & 0x7F) >> 1; + for (i = 0; (i < w_count) && len; i++, len -= 2) + __raw_writew(*p++, info->nand_pref_fifo_add); + pfpw_status = gpmc_prefetch_status(); + } + } + + /* disable and stop the PFPW engine */ + gpmc_prefetch_reset(); +} + /** * omap_verify_buf - Verify chip data against buffer * @mtd: MTD device structure @@ -658,17 +790,12 @@ static int __devinit omap_nand_probe(str err = -ENOMEM; goto out_release_mem_region; } + info->nand.controller = &info->controller; info->nand.IO_ADDR_W = info->nand.IO_ADDR_R; info->nand.cmd_ctrl = omap_hwcontrol; - /* REVISIT: only supports 16-bit NAND flash */ - - info->nand.read_buf = omap_read_buf16; - info->nand.write_buf = omap_write_buf16; - info->nand.verify_buf = omap_verify_buf; - /* * If RDY/BSY line is connected to OMAP then use the omap ready * funcrtion and the generic nand_wait function which reads the status @@ -689,6 +816,23 @@ static int __devinit omap_nand_probe(str == 0x1000) info->nand.options |= NAND_BUSWIDTH_16; + if (use_prefetch) { + /* copy the virtual address of nand base for fifo access */ + info->nand_pref_fifo_add = info->nand.IO_ADDR_R; + + info->nand.read_buf = omap_read_buf_pref; + info->nand.write_buf = omap_write_buf_pref; + } else { + if (info->nand.options & NAND_BUSWIDTH_16) { + info->nand.read_buf = omap_read_buf16; + info->nand.write_buf = omap_write_buf16; + } else { + info->nand.read_buf = omap_read_buf8; + info->nand.write_buf = omap_write_buf8; + } + } + info->nand.verify_buf = omap_verify_buf; + #ifdef CONFIG_MTD_NAND_OMAP_HWECC info->nand.ecc.bytes = 3; info->nand.ecc.size = 512; @@ -746,7 +890,7 @@ static int omap_nand_remove(struct platf platform_set_drvdata(pdev, NULL); /* Release NAND device, its internal structures and partitions */ nand_release(&info->mtd); - iounmap(info->nand.IO_ADDR_R); + iounmap(info->nand_pref_fifo_add); kfree(&info->mtd); return 0; } -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
